Shale retorting process



April 7, 19219 C. H. O. BERG ET AL SHALE RETORTING PROCESS Filed April8. l957 4 lSheets-Sheet 1 ANH 7, 1959 Filed April 8. 1957 C. H. O. BERGET AL SHALE RETORTING PROCESS C f) O C C) @C Q C. H. O. BERG ET AL SHALERETORTING. PROCESS April 7, 1959 4 sheets-sheet 3 Filed April 8, 1957neonunoo Apm 7, 1959 c. H. o. BERG ET A1.

` sHALE RETORTI'NG PRocEss 4 Sheets-Sheet 4 l Filed April 8, 1957 27xzii 9 zza zz.

eduction temperatures by direct or indirect means.

United States Patent M' SHALE RETORTING PROCESS Clyde H. O. Berg andJohn E. Hines, Jr., Long Beach, James R. Hunt, Fullerton, Cloyd P. Reeg,Long Beach, and John H. Ballard, Whittier, Calif., assiguors to UnionOil Company of California, Los Angeles, Calif., ,a corporation ofCalifornia Application April `8, 1957, Serial No. 651,501

23 Claims. (Cl. 202-95) This invention relates in general toimprovements in .solids-fluid contacting and particularly to an improvedwhich oils and gases can be produced by solids-duid contact, and tosolids-fluid contacting processes in general.

Some processes for the eduction of shale oils and gasesinvolve thedownward passage of shale rockas a moving bed by gravity through avertical heat treating kiln. During this passage the solids are heatedto From a thermal eiciency standpoint the direct-heating means in whicha countercurrent contact of hot gases with the lshale rock is employedis preferred. To avoid the large -fuel consumption otherwise requiredmost of these proc- -e'sses involve the direct injection of air orother-oxygencontaining gas into the bottom of the kiln to burn thekkcarbonaceous residue from the spent shale. This geuerates hot fluegases needed to heat therock. However,

`some diiculties are encountered with the fusion of the spent shale dueto this burning, and frequently the fused or partially fused rock plugsthe airinlet requiring a shutdown. Since all of the hydrocarbon productisrevmoved at the top of the kiln, it must be'removed asa -vapor or mistso that the process requires extensive cool- `ing and condensingfacilities and usually results in thermal decomposition of aconsiderable part of the hydrocarbon.

Other shale eduction processes have successfully avoid- Aed the largefuel and condensing water requirements by .utilizing an upflow of shalerock anda downow of heatying gas. The shale is fed upwardly successivelythrough ,a perforated product fluid-shale rock disengaging section landa heat treating and kiln section. Air or other oxygencontaining gasenters the top of the heat treating section, 'is preheated in coolingthe hot shale ash, burns the carmixed fluid phase containing ue gas andoil vapors and liquids. The whole vapor phase ,passes downwardly indirect contact with the cool raw shale, and is cooled thereby condensingthe hydrocarbon oil and preheating the .'raw shale. The liquid andgaseous products are drawn otf at the perforated disengaging section andare thus separated from the upwardly moving shale rock. A solids feederpasses the shale rock upwardly through the disgengaging and heattreating sections anddisplaces the shale ash out the top of the unit.The process supplies its own ...fuel in `the form of`carbonaceousspentjshale. It. cools 2,881 ,l 17I Patented Apr. 7, 195,9

ICC

2 and partially condenses its own product in preheatingthe coolrawfshale rock.

One principal problem of these processes involves the presence of solidsfines in the Vsolids to be thermally treated and in the presentillustration these lines are exemplied by shale lines in the feed. Inthe downilow solids processes, a screening step is required to separatefrom the' rock fed to the process the shale fines whose averagedimensions are less than about 0.25 inch. In the-upowshale process, theproblem is aggravatedwithscrew feeders, andnon-vertically acting pistonfeeders. lWith such solids feeders it has been found that thequantity-of nes in the feed increases as-much as or more when suchsolids feeders are employed andfthat upto about 50% of the feed isreduced to fines in the feeder.y

In the present invention a vertically acting reciprocating pistonfeeder, hereinafter more fully described, Vis used. This piston feedersuccessfully passes shale rock upwardly through the apparatus of thisinvention without the formation of substantial quantities of additionalines. The process and apparatus are also capable of a substantiallycomplete retorting of valuable products from those nes which naturallyoccur in the unscreened feed and thus they accomplish what all theprevious retorting processes were incapable of accomplishing.

In the upflow shale process, the fusion problem is en` counteredparticularly with shales which'producernore than about 30 gallons perton of oil, or where the carbon kcontent of the spent shale isunusuallyhigh so as'to generate an excess of heat during the carbonburn-oif step. These slagging conditions aregnot nearly so serious as inthe downow processfin which theentire weight of vthe solids bed rests onthe fused materials causing it t0 -agglomerate However, slaggingconditions are sometimes encountered between about 2000 `F. and about3000 F., depending upon the mineral constitution ofthe material.

In the present invention these difficulties have beenvsubstantiallyeliminated, yeven in the apparatus applied to commercial scale -solidsprocessing, by the invention shown in the accompanying drawings anddescribed subsequently. Particularly this involves the agitation of the-burning residue in the upwardly rising solids mass. The

agitation is accomplished by means of a plurality of'plows extendingdownwardly intofthe solids bed. TheplQws rotate aboutthe centralvertical axis of the kiln. The

Veffect of this agitation is to preventslagging conditions in theburning zone from inhibiting free and uniform'rgas -flow downwardlythrough the mass of solids being treated. The plows are adapted also tobe self-cooling-,and

`in this way a portion of the heat Aliberated in -the'qburning zone isremoved from the system. The burning zone lis maintained with itsapproximately intermediate'pointor horizontal plane intersecting thelower extremities ofthe plows. Rotation of the plows through the solidsbed prevents the slagging problems referred tovabove.

The present invention is thereforerdirectedto animproved Aupflow shaleretorting apparatus, as illustrative, of

thesesolids heat treating processes Vin which the solids pass upwardlycountercurrent toa downflownofhheat `treating fluid, and in which theburning of residualcarbon on the spent solids is effected in thepresence `ofwfa :substantially continuous agitation inthe burningzoneof-the rising solids by means of the improved-apparatus solids such; `asoil shale, `tar or oil sands, and the like.

It is aparticular, object rofthis invention to .provide fessier-1.7

in such apparatus an improved system for agitating the solids duringcombustion of the residual carbon thereon. A more particular object isto provide, in the upflow -solids retorting` apparatus, animprovedmechanism capable of continuously agitating the burningxs'olids located3 to 6 feet and deeper in lthe rising solids bed, where .the bedcontains solids of up to about 12inches innomi- .nal mesh size, andwhere they are burned at-temperatures betweeni2000? F. and 3000e F. y 1Y A still further object of this invention is to provide a self-coolingheavy-duty solids agitating or plowing apparatus of particular'structural design enabling 'it .to 'ac- ,eomplish successful solidsagitation under the conditions ,referred to above'and yet resist thethermal and merchanical load stresses generated by such hightempera-tures and deep plowing conditions. fr; `Other objects and' advantagesof the present invention will become more apparent to those skilled inthe art as the description and illustration thereof proceed.

The improvedzapparatus, and the particular elements thereof of thepresent invention will be most clearly :described to thoseskilled in theart by reference to the accompanying drawings in which:

.; Figure 1 is a vertical elevation view in partial cross ,section ofthe complete upflow solids-fluid contacting ap- ;paratus of thisinvention as applied to the retorting of oil ,shale and indicates at theupper end thereof the rotary equipment necessary to accomplishA the deepand high .temperature solids plowing referred to previously, `,Figures 2and 3 are elevation views in cross section rfaken at right angles to oneanother showing the plow coolant coolers through which the coolant iscirculated by natural ,convection from the plows and is cooled againsatmospheric air,` f Figure `4 is a plan view of the apparatus shown in,-,Figure 1, butin which the coolant coolers have been .removed for sakeof clarity, land showing the stationary ring girder, hydraulic drivecylinders, the ratchet ring, theplow drive ring, and the central plowsupport ring beneath which by dotted lines are indicated the generalazimuthal disposition of the several plows.

IFigure 5 is a perspective view of the under side of the f plow supportring showing again the azimuthal disposition ofthe plows, theirconnection to the lower surface of the plow support ring, and the mannerin which ,they extend downwardly in a helical curve and are terminatedat'their lower ends in an abrasion resistant plow shoe, and

Figures 6 through l2 are cross sectional views of the plows takenat theplaces indicated in Figure ,5, and which showin detail theinternalconstruction of theplows .18nd shoes. l .4

,Referring now more particularly to Figure l, the entire apparatus inwhichthe particular :improved solids agitation or plowing mechanism ofthe present invention `.:,iS 1.lSed, is shown in the form in which theapparatus is applied to the continuous retorting of oil shale to produce-shale oil and gas. The apparatus consists essentially of a feedercase10,a formaminatesolids-uid disengaging means 12, and heat treating orkiln means 14'superimposed one above the other in the manner shown.Super- `imposed at the top of kiln 14 is the entire rotating mechanismemployed in the present invention for agitating continuously theburningsolids. a Oil shale is introduced into'fhoppergl andvis fed by 4means ofthe solids feeder upwardly successively through vdisengaging zone 12 andretorting zone or kiln 14. The solids feeder comprises a-solids feedercylinder 18 disposed within feeder case and supported from trunnion .20permitting ityto be oscillated in a verticalV plane so that the upper4opening ofthe cylinder is aligned alternately with the Ybottom of hopper16 'and the lower solids inlet to `disengaging zone.12. IThe hydraulicfeeder cylinder v22 provided with piston'rod 24 and feederpiston 26,' isdisposed within solids feeder cylinder 18 and oscillates with it.Guardsor shoes 28 and 30 c'urvcaway from the sides of the upper openingof feeder cylinder 18 and serve to close the lower outlet of hopper 16when feeder cylinder 18 is in the position shown, and also to close thelower solids entrance to disengaging section 12 when the feeder cylinderis oscillatod tothe left in registry with the shale hopper. Theoscillatory motion of feeder cylinder 1S is provided by means of'oscillatingfhydraulic cylinder 32 connected at pivot 34 to theinside offeeder case 19, and also conneted't pivot 36'by means of pistonrod 38 tothe side of feeder cylinder 18.

v/The cyclicaetionI ofhyd'raulic cylinders 22 and 32, necessary toachieve the removal of fresh solids from hopper 16 andthe introductionthereof upwardly from below into the vertical path Ithrough disengagingsection 12 and heat treating section 14 consists of four repeated steps.First, the oscillating hydraulic cylinder 32 re tracts with hydraulicfeeder cylinder 22 in the position shown inclining solids feedercylinder 18 to the left into alignment with shale hopper 16. Second, thehydraulic feeder Vcylinder 22 retracts moving piston 2 6 downwardlytoward trunnion 20 drawing a charge of fresh shale and any recirculatedfines into the top of feeder cylinder 1 8. At this time guard 30 sealsthe lower solids entrance to disengaging section l2`. Third, thehydraulic oscillating cylinder 32 extends moving feeder piston 18 backinfo the Ivertical position shown, butin which piston 26 is at itslowest position, not shown. Fourth, the hydraulic feeder cylinder 22'extends forcing the charge of raw shale upwardly into theV lower part ofdisengaging section 12. The entire'mass of solids moves upwardly throughsections 12 and 14 and some sp ent solids discharge at the top of heattreatingsection r14.l At this time guard 28 is in vthe positionshownclosing the lower outlet of t h e shale Yhopper'. These vfour s teps,are vthen repeated to maintain4 a substantially continuously upwardflow of solids. l

Avided alon`g the `bottom of feeder case V1 0 extending j n the generaldirection o fjlthe `plane of oscillation and closely beside trunnion 2 0for m ing in hfeeder case 1 0 a `Vlshaped bottom. long theulowernline of intersection 'f this trough is estende@ wsu .Conveyor Y44, drivenbyrotary means not Jshown Jbut conventional. This conveyor removes smalltraces of solids fines which sometimes 'leak past guards 28 and 30and accumulate in the feeder case. 'lo assist conveyor 44, a stream ofproduct oil is introduced under pressure into feeder case 10 .throughline 46 and is removed in the formof a fines slurry from outlet 48 atthe discharge end of the conveyor-1 This slurry .is Pumped by msansofpump S0` am rate 'Controlled by valve .5.2 rhQUsh line. 54 either. intothe bottom of hopper 1 6 or into nes distributor 56.

As indicated previously the ysolidsmove successive-ly in an upwarddirection as a dense, fluid-permeable, continuous mass througl1 theperforated duid disengaging section 12 .and through heat treatingsection 1 4. The downward'counter'current flow of fluid is maintained bymeans of gas blower 6 0 which takes 4suction through line 62 atthe upperend of product separator chamber 6 4 surrounding the perforateddisengaging section 12. Air therefore enters thetopof heat treatingsection 14, and the llow of fluid passes downwardly successively throughash cooling and air prel 1 e 2 1ting zonev 66, spent shale Aburning zone68, retorting ,or cduction zone 70, -raw shale preheating and productfluid cooling and condensing zone 72, and continues into fluid separatorsection12. The fluid ows, still under the influence of blower 60,through perforations 74 into product separator 64. The

condensed shale oil accumulates in the 'lower portion of product 'sep'ato 4 providing aliquid levelat the 4 ap- 'product"separator`f'64"is'provided- Vwith a VV- shape'd bottom comprising tw'o pair of"inclined baffles, lone of whichy indicated as 478 and the-intersectionof vertical passageways. 'ends to4 flow of air by natural convectionwhich serves `to cool the metal wall of heat treating section 1 4. 'A'

ais 1511 i 7 viewed at 90 from the drawing present the VV-"shaped crosssection. Along the bottomof eaChV-Shap'ed pair fof baies is extended aprimary screw conveyor, one' of "fwhich is indicated in Figure'l at 30.lw'ithrotary drive means 82and delivers settled solid 'shale nes, whichfall throughl slots 74 and 4settle inthe liquid product, into transversesecondary conveyor 84; The `lines are here accumulated from both primaryconveyors and discharged by means of conveyor 84 into lines distributor56.

f This distributor is centrally located at the bottom of ""slale hopper16 so that the vfnesare concentrated in the" interior of the charge oflarger sized shale particlesinto `w l1`i `ih"they are introduced. Thisprevents any"subse "quent fall-through of these same fines into productsepafratorv chamber 64 and insures that they be carriedup-v wardly withthe raw shale feed and treated therewith""'l It is provided in heattreating section 14.

As indicated previously, the liquids and' the gases vseparate from eachother in separator chamber 64. The lv-1liquid phase, principally shaleoil, ows from separator 64 through line 86 under the inuence'of'product'oil'i' "pump 88 at a rate controlled by valve 90 andliq'uidlevel controller 92. Part of the product ilows as previ- `v,ouslydescribed through line 46 controlled by valve `94 to ilush solids finesfrom' feedercase 10.

rBlower 60 previously described withdraws non-condensed gases 'from theupper portion of separator'64 and v p'asses them vthrough linev96 intomist separator 9S at i'a rate controlled by valve 100. Pressurecontroller'102 "nay control valve 100 in order to maintain a predet`er-. 'nined subatm'ospheric pressure in separator chamber" 64, ""or' litmay, if desired, maintain'a predetermined differentialy pressure betweenthe top and the bottoml of'heat treating section 14. In mist separator98 residual traces of entrainedli'qulds are separated from the gasstream and are passed through lline 104 controlled by valve 106 intocombination with the shale oil product produced through line 108. Thenon-condensed gases flow through line 11i) provided "with valve 112.VOrdinarily these gases are discharged to the atmosphere and theycomprise essentially carbon "monoxide, nitrogen, and carbon dioxide withrelatively small amounts of hydrocarbon gases suflicient to give the gasa heating value of about 90 Btu. per cubic foot. @This gas may be usedas fuel with special burners,"or "if desired, part or all of it maybereintroduced as re' ycycle gas into 4the top of heat treating section 14Yto dilute the incoming air in order to moderate combusvtiontemperatures and the conditions of eduction.

cylindrical elemenfdispo'sed 'verticallyv WthtsfaX'iS's'ubstantiallycoincident with "the l've'rt'ical-y axis 'of disengag- `ing section' 1 2and"heat eating sectionilt. Aring ""gi'rder 130 is disposed'ar ndfthe'upper end'of` -fra'me'128 'and serves"to srelgthen'the"upperedy thesideframe. Drive ring132 cisistsof uppeitiange lelement "13'4, upper"cylindrical" section 136, li'ori'z ntal "o r pltfornfsection'lSS," intemed ecylindrical "140, lower'cylindrical ""section" section 144. `Thedrivering "is ffdrsp'osed'in ai generally 'horizontalposition`within"ring'g irder 130. l`A-"plu'r ality of horizontal 'thrustvrollers" 146 ``witl 1"'th eir aXesver'tiCal areA supportedat uniformlyspaced locations 'around'ring `girder 130.The'peripheryof'drivewring:132turnsjn contact with the primarybearings'in'order to mai 'in theA SSOciated plow /qlllpfllehtmiiaACeltzll/ p''S'tn. plurality of vertical thrust rollers 143 disposedwith-"their vaxes horizontal are uniformly-spaced around 'ring girder'turning'inthe upwardly mo`ving"'solit is' bed. Horizontal rollers"146"th1.1s1ridewiny peripherali'track 149 disposed Heat treating section.1d-'is conical in shape, as is"dis yengaging section 12, but has aconsiderably smaller apexiV angle.

It is provided on its outer surface with a plurality of verticallyextending radial ns 114, the outer edges of which are enclosed in jacket116 providing a series These are open at ltheir lower manifold 119communicates the upper ends of each'of the vertical passageways and thewarmlair passing there-l through into the manifold is discharged totheatmosphere through one or more stacks, not shown, but which communicatewith manifold 119. j

Disposed horizontally around and just below the-up- 122, Ashrdischargechute 124 opens downwardly from the bottom of platform 118 at one sideof the ash con- ..f :.,veyor. .z ,The ash is moved around ashl conveyor120 to this discharge" point by`r`neans` of a plurality 'of scraperv`around theV outer surface'ofdrive ii'ng 132 'jst outside of'intermediate' cylindricallsetifon 140, ,'The conveyor elements 1264 areat`t ache'd""by"'the means shown'tdthe *drive ring just described androe 'with`it. Disposed around the inner 'surface of"ring`?'g'irderl sidedrame 123"and j'ust below the'ring'girder 130 is` "an"` ,i shapedchannel 129 containinga bed 131 of'fnesolids 'such as sand. Channel 129isof coursestationary. Supported from the outer (surface of lowercylindric'al's'ection`142 of the drive ring 132 'is rotatingseal'elerne'nt 133g having an'inverted' L-sl'i'pe which eXterds" entirely around the'drive'ring and"al"so"er i ten`ds downwardly'into sealsolids bed 131. This-'seal 'prevents entryof atmospheric air intothe'kiln 'l'lnd'ethe"influence` of vgas blower 60 around the periphery'of vtlieldrive''ring"'ancl forees the air flow to enter via"fas hchute"1 `24. vr`In 'soowi'ngfin "through the'ash chiite, 'theairen'tering is counte'rcil'rrently contacted by the discha ging'ashthereby :effecting asignica'nt degree"ofiash'eooling'ancl'airprelieafing.

Disposed aroundv the outerf'edg'eofupper'flange'sec- 'ition 134 isaT-shaped' ratchet ring 1'50. Theweb of thisring' is bolted tothe outer"edge" of"upper"flange"ele ment 134 and providesa pluralityfofflatvertical ratchet 'surfaces on its verticalflangeag'ain'st"which'the"driving 'mechanism' hereinafter" described'enga'gesto vvapply: the tangential turning force. "In"th is" way' the`drive"ring"is rotated. These driving forces "arefy applied'hydraulically and continuously 'at power 'levels "suiifc'ient'y to'rotate the drive ring at avelo'city betweenabout 1-and abonenrevolutions per hour.

superimposed above upperf liange elernentwlltw" are one'orIrnore'spacer'rings 152 `nd .1 54. "The purposef these rings is toraise/'orflower e'plows vwith respect to the drive` ring 132 rand Athevujv'warfdly-l movingshalefbed. The spacer rings; are`ess`ent'ial1y"`curved' channel` b "m sectionsyconnected to one anotherin acircle'with fla ges outwardso' that they aref'readilyaddd orremoved" from .'"the side of the rotating-v structure. f

:neuerer-.erba moulin-emi. the retort .structure.-.;1Jtitit'proyidcd-fwithf-a loncrndeek, 16.6,. uppendeck. 174, .and bylithinternal bracing notahown.- .The Ythree .plows..16 0, 3.1.62;@1164 are.dependent from the lower deck, 166 of plow support -rin g 156; by rneansoftransition sections -.168,. .17.0, and 17a-respectively..

Supported onippncr. deck 17.4 .of .the plow Support Lring tare.disposedthe plas/Coolant c1ers 1 .76, 1787 and, 180 TI-he structure ofthesecoolers and-their` operation is more 5 tain any desired minimalinert gas pressure in theA sysptem.YI A gas vessel 226 provides areservoir for the gas. under slight pressure. When the apparatus is'cold and beingstarted up, coolant as well as gas expansion toccurs andthe pressure may tend'to rise above a certain ,dem-1ydescribedfincgonnetionwith Figures 2 and 3.010 'xed ,maximum value.Accordingly bleed line 221is .Suice it heretof sayl -however `that thesecoolers are provided with suitable piping connections indicated gen--.erall yas 1 82 bymeaus of which the liquid coolant from Ytheplowstlows upwardly in to vthe cooler and then is returned for,circulation'through-- the plow.- l The previous descriptionindicatesgenerally the upow solids-tinidcontacting. process and apparatus ofthisinyention and generally pointsiout the relationship of thevself-cooled shale plows and therotating mechanism with provided'withvalve 230 which is actuated by .pressure *controller 232. The setting of`pressure controller 224 in a system using liquid sodium as the coolantand helium as the inert blanketing gas may be 0.5 p.s.i. forpres- :.15Sure controller 224 and 1.0 p.s.i. for pressure controller 232. Ifdesired, these lines 220 and 228 may be connected with compressor meansand gas storage means not shown .so that a closed inert gas system isemployed. In this `way substantially no internal fluid pressures areexerted -the upow shale retorting apparatus. The following cle-Q on theplow-cooler structure. y

scription of Figureslfthrough 12 is restricted to the structuraldetailof the plow support ring, the plows der pendent therefrom, 1 the.coolant cooler superimposed l. thereon, andthe means by which therotating element is ,-,turned and maintained in a fixed position duringthe rota-.125

,.Referringnow more particularly to. Figures 2 and 3, isshowntheinternalstructure of each coolant cooler. -`The upper deck 174 of plow.support ring 156 is shown to- .gether with hotline 190 andcold line 192opening u1u-5,30

'wardly into and downwardly from the coolant cooler. =`Oute`r shell 194.isprovided and it is supported from upper deck 17,4 by,any form ofconvenient support structure .not shownbut indicated schematically inFigure 1.

Hotline 190 opens into .horizontal hot header .196 and-35 the horizontallegs of which are provided with external- 40 vertical fins-to increasethe heat transfer area. Disposed ,immediately aboyethe ,bank of finnedtubes is fan 202 supportedand driven from shaft 20.4 which connects toelectric motor-206'. The purpose of the fan is to force coolingairdownwardly within enclosure 194 in the di- A -f rection of the arrQWSacross the finned surfaces of the tubes, into bottom lporton ofenclosure 194, back upwardly through channels 208 and 210 to the top ofenclosure 194.V Ihe reverse direction of air flow may be us'ed ifdesired. Louvres 212 and 214 are manually ad- 50 justed'jby means ofcontrol element 216 and maydirect `the coolingair onevthrough across thefinned tubes, or 1 it `may discharge part ofthe heated air and introducesomenew cooled, air, orit may recirculate the air entirely withinenclosure 194. One or the other of the irstjtwo cases mentioned ischaracteristic of operation after operating temperatures have beenreached within the retort proper, IThe latter air flow plan ischaracterr. istie. 0.1. the starwnperiod.

Q Asa further aidin starting up, resistance heaters 191 60 cold lines190 and 192. Heater 195 is provided in the lenclosure 194 to heatairthereinwhich is circulated by -1851.202 to. melt. the coolant. in thenned Urtubes 20D .An...adsiitional.bones19?. isrrcvded around reservoir65 The, coolant v,circulatestty natural convection through hot line 190throughtlewcoolangcooler and back into 70 .aasi-tht0usame .plea/renamed. therewith .through cold line 1192.1; Singe, theJ coolantxexpands and `contracts betwgen. the shutdown .and ,operating extremes,of l temsperaturegaudbecauselitmay be chemically reactive, an

- pressuringrgasisgitroducdeinto. theisystemgthrpugh .75

It should be understood that 1n the present modification three plows arejshown attached to the lower deck of `plow support ring 156 andacorresponding `number-'of coolant coolers are supported on the upperdeck. This particular number is lnot intended as a limitationin the;apparatus of this invention since fewer than threeas well as more thanthree plows and corresponding coolers may be employed depending upon thesize of the retorting equipment, and particularly its upper diameter.

Referring now more particularly to Figure 4, a partial plan view of theapparatus of Figure l is shown in-somewhat greater detail. Ring girderside frame 128 appears together with the ring girder 130 at theupper-end thereof. Disposed-at uniform intervals aroundthetpeyriphery ofring girder 130 arev alternate horizontal thrust ...rollers 146 and.vertical thrust rollers 148 by means of which the rotation of the plowdrive ring is guided.

The horizontal platform surface 138 of plow ldrive ring 132 is shownhaving a small clearance 240 between Aits outer edge and the innersurface of ring girder 130. Upper flange element 134 of the drive ringis provided with an inner and outer bolt circle. Ratchet ring'150.isshown bolted to the outer bolt circle and its configuration is clearlyshown in this figure. To the inner bolt circlev is bolted plow supportring 156. t

Disposed around the inner surface of ring girder 130 are stationarycleats 242 by means of which each hydraulic drive cylinder 244 ispivotably anchored in a stationary position. Ratchet ring engaging heads246 are connected at the end of each of the piston rods of the hydraulicdrive cylinders 244. Shoe guides 248 ride laround and overlap the upperand lower exposed edges of ratchet ring and maintain engaging head 246ina substantially fixed radial position with respect to ratchet ring 150.Engaging head 246 is spring loaded by means of spring 250 so that it isbiased radially inward att-'its extreme end into continuous contact withthe outer surface of the ratchet ring. Thus as each hydraulic drivecylinder..244 is extended, shoes 248 prevent radial outward movement ofengaging head 246 and the engaging head engages the ratchet ring so thatthe drive cylinders can apply a tangential rotating force effectively tothe periphery of the drive ring.

Although Figure 4 isv `fragmentary view of approximately one-half ofthe'ring girder, of the drive ring,and of the ratchet ring, and showingthe entire upper surface of the plow support ring, it is apparent thatsix'drive cylinders 244 are provided spaced 60 apart around the annularspace between the ratchet ring 150 and the inner surface of the ringgirder 130. To obtain continuous rotation of the rotary equipment, itismostA4 desirable .that at'any given' time in the' cycle a first pair of.th'e'se six hydraulic drive cylinders is being retracted and thenpre-engaged with the ratchet ring by theI application. of .lqwhydraulicoil pressure while.the second-and third pair are at` two diiferentstages of completion of their power strokes. At the time that the iirst-pair just begins v`the retraction and pre-engagement strokes, thesecond pair is just `beginning the power strokepwhile in the third ypairthe power stroke is approximately 50% complete. The third pair of coursewill complete the power stroke before the second pair. As soon as thiscompletion occurs, the iirst pair of cylinders, which has now beenretracted and pre-engaged under low-pressuring, is thrown immediatelyinto the beginning of the power stroke while the retraction andpre-engagement continues with the third pair which has just completedits power stroke. This sequence of operations continues in -a cycle tomaintain steady rotation at very high torque andvery low `velocities offrom about l to about 6 revolutions per hour.

Also shown in Figure 4 is lthe structur'lewof plow sup- .,port ring 156.The upper and lowerdecks are segmented and consist ofllat plates 252welded at right angles to vertical stiifening plates 254 which projectfrom above the upper deck to below the lower deck forming flanges. Theseplates 254 are drilled horizontally in the flange portions so that allthe sections maybe bolted securely together. The underside of thisstructure including the ilanges is shown in the attached Figure 5subsequently described.

The azimuthal and radial distribution of the three plows on plow supportring 156 is also shownV in Figure 4. For example the outermost plow 256is provided with yshoe 258 and transition section 260 by means of whichit is connected to the lower deck of plow support ring 156. Openings 262and 264 are provided r`in` the upper deck of the plow support ringthrough which extend hot line 190 and cold line 192 respectively forconducting the coolant ow between the plow and the coolant coolers. y l

In the present modification three such plows are employed. They aredisposed radially with respect to vthe center of rotation 266 of theplow support ring and azimuthally with respect to one another so thatnet resultant horizontal force on the plow support ring is as nearlyzero as possible thereby minimizing the load on 'the horizontal andvertical thrust rollers mounted in the ring girder and thereby alsoequalizing the loads on each of the four hydraulic drive cylinders whichare in the power stroke at any given time. y

The radial dimension of the leading `edge of each plow shoe 258decreases successively with plows disposed radially farther from thecenter of rotation. In other words the innermost plow has the widestshoe and the plows dispose-d farther out have successively narrowershoes. Furthermore, the radial disposition of the-plows yfrom the centerof rotation 266 isadjusted with respect to the relative shoe widths sothat the entire cross section of the rising mass of shale is swept andagitated bythe leading edge of a plow shoe once for every rotation ofthe plow support ring, with the exception of a very small section at thecenter of rotation and a Very thin` section adjacent the outer edge ofthe rising mass of shale. This is shown schematically only in Figure 4.

Referring now more particularly to Figure 5, a perspective View of theplows as viewed from beneath plow support ring 156 is shown. Thestructurerof allwplows is generally the same, each has the same numberofcorresponding elements as the other two, andvonly the physicaldimensions vary somewhat from plow to plow.

The individual flanged sections of lower deck v166 clearly appeartogether with the drilled holes required in the anges for bolting thevarious sections together. The three plows shown are located alongdii-ferent radii from the center of rotation, plow 162 being closest tothe center, plow 168 being located at an intermediate radius, and plow164 being located nearest the periphery of'plow supportring 156. y i Ingeneral the helical curvature of the leading'fand trailing yedges'or-struts of plows 160; 162, andel'64''`s apparent in this ligure, thecylindricalcu'rvature ofthe plows being particularly apparent withrespect to .plow 162. Each of these plows is provided at its lowerextremity with a plow shoe 270, 272, and 274, respectively, and eachplow is connected to the lower deck 166 of plow support ring 156 bymeans of transition sections 168, 170, and 172. i

Referring now to transition section 172 as representative of the othersas well, the transition section is fabricated from leading conicalsection 276 and trailing conical section 278, both of relatively smallradii'and disposed with their apices downward, spaced apart from oneanother along an arc around the center of rotation. The transitionsection is then completed by interconnecting the open edges lof theleading and trailing conical sections referred to by.means of innerconical side section 280 and an outer conical side section not shown butcorresponding to outer conical side section 282 in transition section168. These conical side sections have large radii relative to the radiiof the leading and trailing conical sections. The curvature of theseconical side sections is such that the cone from which the inner conicalV`sec` tion 280 is taken has its apex upward while the cone -from whichthe outer conical section corresponding to 282 was taken has its apexdownward. The slope of the sides of all of the four conical sections ineach transition section is the same.

The structure of the transition section thus formed comprises a closedexterior surface, welded at its upper edge to lower deck 166 of plowsupport ring 156, which curves along an arc around the center ofrotation o f the plowA support ring, and which tapers downwardly. Eachof the three transition sections 168, 170, 172 is constructed in generalfrom four such conical sections. The radii of the conical sidersectionsare selected-so that the inner and outer sections join with the conicalleading and trailing conical sections tangentially, such as at welds 284and 286 in transition section 172.

The transition sections are each extended downwardly a short distancebelow a horizontal adapter plate 288 shown more clearly in Figure 6.This extension exists all the way around the periphery of the adapterplate,

except adjacent the trailing conical section 278. At this' point it isprovided with a helicoid surface 290, the helical slope of which issubstantially identical to that of the trailing strut of the plow164.The purpose of this cutaway portion is to prevent exposure of any athorizontal surfaces against the rising'bed of solids. Such slopingsurfaces are provided so as to have a slope whichexceeds the get-awayangle.V This angle is expressed in degrees from a horizontal referenceand is defined as the angle necessary to keep any submerged surface fromrestricting the upward movement of solids at a time when the solids feedrate is at a maximum and the plow rotation rate is at a minimum. For theretorting of shale in the apparatus of the invention as described inconnection withFigure 1, this `angle was approximately 15. Helicoidsurface 290 had a slope of about 33.

Referring now more particularly to plow 168 as representative of theother plows also, this member is cornposed of a leading strut 292 and atrailing strut 294, each of which is bent into a helical curvevofdifferent angles so as to converge toward one another. The struts arehollow tubular members yof circular cross section. At the point ofconvergence-of these struts plowshoe 270 is securely attached. The tubelradii'of the leading 'and trailing helical struts 292 and 294 arerelatively low. The exterior surface of plow is completedby 'an innercylindrical side section, not shown but corresponding to-section 296 onplow v1164,.'and an outer cylindrical side section 298,'ea`ch ofrelatively large'radii. These inner 'and outer cylindrical sidevsections are concentric with each btherand'are welded *at their edgestottl'r'e leadgand t'rilinglielical vstruts 292 and 294vatth`e locus of?innermost and outermost tangent points, respectively, of each strut. 1 y

-1 The detail of the inner structures of the transition sections, theplows, and the plow shoes are illustrated in Figures 6 through l2hereinafter more fully described'. These drawings are all sectionalviews of the complete plow element, and these sections are taken in thedirections indicated in Figure by the section lines shown o n plow 162,as well as in Figure 6. d' Referring now more particularly to Figure 6,a developed vertical cross section view through plow 162 is shown. Thisis a view of the plow support ring 156 with its upper and lower decks174 and 166 respectively, and showing transition section 170, plow 162,and shoe 272 as they would appear as if plow 162 and its transition-section 170 were cut in the manner indicated in Figure 5 and viewed atright angles from the axis of rotation. Leading conical section 276 andtrailing conical section 278 of transition section 170 are shown.Extending upwardly from adaptor plate 288 are hot line 190 and cold line192 by means of which the plow coolant is circulated through `thecoolant coolers previously described. Vertical stiffening plates 300disposed radially within transition section 170 between the conical sidesections previously described are employed to strengthen the structure.

Extending downwardly and to the right at a helix angle bf about 45 isleading helical strut 292. Leading downwardly and to the right at anangle of about 33 is trailing helical strut 294, the adjacent parts ofthe leading and trailing struts converging at point 302. As indicatedpreviously, each of these leading and trailing struts i's nhollow andcylindrical in cross section and thus form `aiiow path for the plowcoolant downwardly from cool line 192 into plow shoe 272, and from theplow shoe upwardly toward hot line 190r and the coolant coolers in 'thedirection of the arrows.

The outer envelope of the plow element is completed byy means of theinner and outer cylindrical side sections 296 and 298 not shown inFigure 6, but previously described in connection with Figure 5. Thisforms a hollow structure which is closed at its lower end by means 'ofshoe sole plate 304 and plow shoe 272. The plow and shoe are welded orotherwise attached securely together forming a tiuid tight envelopesupported from adaptor plate 288. In general this structural elementcomprises a helical hollow cantilever beam.

"Since the thermal and mechanical stresses to which this beam issubjected during plowing of the burning shale are quite severe, furtherinternal strengthening of this outer cantilever beam is frequentlydesirable. This is accomplished by providing a second or innercantilever beam supported also from adaptor plate 288 and which extendsdownwardly at an angle in a curving path in the space provided betweenthe inner and outer cylindrical side sections referred to previously andalso between the leading and trailing struts of the plow. This innercantilever beam comprises a plurality of converging helicoids 306, 308,and 310, the upper ends of which are spaced apart from one another alongthe same radius as the leading and trailing struts 292 and 294 on thelower surface of the adaptor plate 288. These particular helicoidsYare'helical surfaces generated by radii extended at right angles fromthe longitudinal axis of a cylinder through a helix scribed on thesurface of that cylinder. These helicoids converge toward anintersection 312 near the intersection 302 of the adjacent surfaces ofleading and `trailing struts 292 and 294 of the outer cantilever beam.The innerand-outer edges of the three helicoids are connectedrespectively together by an inner and an `outer` cylindrical sidesection forming thevinner cantilever beam having a curved III-shapedcross section when three heliclzoidsv are employed. This is l2. j"Tha/completed plow 'elementthus-comprises an outer cantileverV beamcomprising a pair of converging helical struts and the associatedcylindrical side sections surrounding an inner cantilever beamcomprising converging helicoids and their associated cylindrical sidesections, both the outer and inner cantilevers being anchored at adaptorplate 288 in the manner shown generally in Figure 6. The adjacent outercylindrical side sections andthe adjacent inner cylindrical sidesections form double outer and inner metal walls of the plow structure.

Disposed at spaced intervals along the rear of trailing vstrut 294 areparallel void sealing plates 339. These are nearly horizontal plateshaving the transverse shape shown in Figure 10 and are provided toprevent gas flow down through an elongated helical void which may existbehind the trailing strut.

Referring now more particularly to Figure 7, which is a plan view of theplow shoe, the intersection of leading helical strut 292 with plow shoe272 is shown. The leading edge of the shoe is protected by a wear plate320. The shoe consists of generally triangular-shaped lower or sole andupper surfaces 304 and 322 respectively. The coolant flow is in thedirection indicated by the arrows in Figure 6, namely downwardly throughtrailing helical strut 294 toward the plow shoe 272. A first portion ofthe coolant bypasses directly through primary bypass opening 324 wherethe helical struts 292 and 294 have converged, then directly into theleading helical strut 292, and then upwardly toward the coolers. Theremaining portion flows through entrance 326 into plow shoe 272. Herethe flow splits with a first portion leaving the shoe through secondarybypass opening 328 and ows directly into leading strut 292. The portionof coolant remaining in the plow shoe 272 is directed laterally towardthe inner tip of the shoe'by means of primary baiile 330, extendingangularly from the outer portion of the shoe toward the inner portion.This flow again splits and a first portion flows through opening 332between primary baille 330 and secondary baie 334. The remaining portionis directed around the end of secondary baffle 334 and progresses backoutwardly along the leading edge of the shoe into admixture with firstportion flowing through opening 332. This combined ow then passes backtoward the outer edge of shoe 272 along the leading edge thereof and owsthrough outlet 336 into leading strut 292.

The entire coolant flow is reformed then at the lower extremity ofleading strut 292 and progresses upwardly in the direction indicated bythe arrows in Figure `6. Part way from the shoe 272 to the adaptor plate288, part of the coolant stream enters the inner cantilever beamstructure through openings 321 in the leading strut and openings 323 and325 in the helicoids. It then flows parallel to the remaining flow inleading strut 282 through the inner or helicoid cantilever and re-entersthe leading strut 292 via openings 327 and 329 in the helicoids andopening331 in the strut. The entire coolant stream is again reformedjust below adaptor plate 288 as the coolant flows upwardly through hotline 190. Additional openings 333, 335, and 337 are provided in the rearhelicoid and in the helicoid side sections to maintain the space betweenthe double walls of the plows filled with coolant.

Referring now more particularly to Figure 8, a plan view in crosssection of the transitionl section shown in Figure 6 is illustrated.'The four conical sectionswhich make up the transition section areclearly shown in this drawing. The leading and trailing conical sections276 and 278, with their apices downward, are shown joined tangentiallyto the inner and outer conical side sections 280v a nd 282 with theirapices upward and downward respectively. Adaptor plate 288 appears atthe `bottom of transition section and the coolant riser lines and 192are shown. The radial stifening plates 300 are connected across betweenthe inner and outer cylindrical side sections.-

more clearly shown in Figure 10 subsequently described. 75 l Referringnow more particularly to Figure 9, an end v deck 166 ofthe plow supportring. of inner and outer cylindrical side sections 296 and 298 f theouter cantilever beam are shown attached to trailelevationview'ofthe'transition section across section'is shown. Riser line 192extending upwardly from adaptor plate 288 is shown. The sloping innerand outer conical side sections 280 and'282 are shown attached to lowering helical strut 296. A portion of the inner or helicoid cantileverbeam is shown including outer and innercylindrical side sections 314 and316. The upper end of the .trailing helicoid 306 is also shown. Thetapering nature of the transition section and the manner in which itisconnected by means of the adaptor plate to the inner and outercantilever beams are clearly` apparent.

Referring briefly to Figure` 1,0, trailing cylindrical heli` cal strut294, with one of the attached void sealing plates 339, and leading strut292 together with o-uter `and inner v cylindrical side sections 298 and296 making up the outer cantilever beam are shown. V.and leadinghelicoids 306, 308, and 310 respectively, to-` gether with the outer andinner cylindrical helicoid side The trailing, intermediate,

sections 314 and 316 respectively, make up the inner cantilever beam.These two cantilever beams are anchored to adaptor plate 288 as shown inFigure 6. The

inner cantilever reinforces and stiifens the outer cantilever by directmechanical contact in the region of helicoid intersection 312 also asshown in Figure 6.

The pairs of immediately adjacent inner cylindrical side .sections andouter cylindrical side sections of the inner .and outer cantileversrespectively comprise the double .inner and outer walls of the plowwhich provide the strength necessary to agitate the solids duringcombustion and through which heat is transferred from the burning solidsto the coolant. It is absolutely essential that the thin space betweenthese two double walls be filled with y coolant to present a very lowthermal resistance to heat ow into the principal coolant flow whichpasses upwardly between the helicoids. Therefore apertures 341 yand 343are provided in the outer cylindrical section 316 .and apertures 34S and347 are provided on the inner cylindrical section 314 of the innercantilever in order to insure the presence of an analogous liquidcoolant iilm between the inner and outer cylindrical side sectionsrespectively of the inner and outer cantilever beams. Openings 341 and343 are also shown in Figure 6. It is not .believed that any substantialflow of coolant occurs between the double walls, but the presence of thecoolant markedly facilitates heat transfer therethrough into theprincipal coolant flow within the inner cantilever.

Referring now more particularly to Figure 11, this is a cross sectionview of the composite plow structure taken substantially at the point atwhich the inner cantilever.. lbeam converges with vthe outer beam.4 Itis analogous. .to the section shown'in Figure l0. The leading andltrailing helical struts 292 and294 together with the inner', and outercylindrical side plates 296 and 293 are shown.

The inner or helicoid cantilever again appears showing the addition atdifferent points of curved bearing plates 340 and 342 by means of whichthe end of the inner cantilever beam is loaded by deections of the outercantilever beam. Reference haspreviously been made, with respect to the.doubley walls comprising the outer cylindrical side plates and the innercylindrical side plates of the co-ncentric cantilever beams, to theimportance of the thin `'film ofcoolant within these double walls.Vconsiderations are important with respect to the wear plate 320 whichis disposed around the leading edge of plow shoe 272.

The same In Figure l2 is an enlarged cross section elevation view of theplow shoe 272 shown in Figures 5, 6, and 7.

:The lower end of leading strut 292 is shown converging with uppersurface 322 of plow shoe 272. surface curves around the ltoe 344 andbecomes sole plate v`304. `Wear plate 320 is wrapped around the outsideThe upper The upper edges 'side frame shown in Figure 1.

j steel pipe bent into a helix.

diameter of 6.0 inches.

was 5.5 feet.

of toej 344 of shoe 272 and -spaced uniformly 'therefri by meansofspacers 346, Thel Wear plate is welded acrossthetop lsurface 322 andacross sole plate 3.04

and along the nearly verticaly sides of the shoe"as'indi cated byweld'348. This forms between toe 3 44`and wear plate 320 a thinsemi-cylindrical space 350 into which is introduced a volume of coolantliquid sufficient to fill the space through opening 352 in the end ofthe This provides for ready heat transfer through 'the wear plate andthe toe into the leading edge of the shoe through which the coolant iscirculated. Opening 35 2 `isl permanently closed after the wearplate'volume 350 'is iilled. f

The apparatus ofthe present invention was applied in the retorting ofColorado oil shale analyzing between about 28and .40 gallons. per ton.The feed rate'was .350 tons per day. The solids feeder vcylindercontained within the feeder case. was 5.5 feet in diameter and had astroke of 2.0 feet. The height of the apparatus to the top of the ringgirder was about 46 feet. The outside diameter ofthe entire structure atthis point was about 30 feet, this being the outside diameter of thering' girder The plow support ring was 16 feet in diameter and 2.0 feetin thickness and supported three plows substantially as indicated inFigure 5. The inner and outer cylindrical side sections of ythe -innerand outer cantilever elements of the plowswere yfabricated fromstainless steel plate about 0.5 inch. in

pipe provided with transverse radial aluminum tins spaced 0.25 inchapartfrom each other and having an outside The inned length of eachV loop Afan driven by a 7.5 horespower motor was disposed over each bank offinned tubes.

The coolant selected for this system was metallicsodi- 45v um andtheinventory in each cooler plow combination was approximately 2000 pounds.The circulation. of molten sodium within the plows was by naturalconvection andat a rate of about 9000 pounds per minute.v During normaloperations the temperature of sodium into the coolers was about k425 F.and that out of the coolers lwas about 375 v Other coolants may besubstituted, such as the sodiumy'potassium (NaK) eutectic, lithium,potassium, molten ysalts s uch. as the alkali metal nitrates andnitrites, lead,

andthe like. Forvoperation under pressure, waterv may be circulated orboiled in theplows. The enumerated materials are intended asrepresentative non-exclusive, suitable heat transfer agents. Aparticular embodiment of the present invention has been hereinabovedescribed in considerable detail'by way of '.illustration. .It should beunderstood that various other modifications and adaptations thereof maybemade -by those skilled in this particular art without departing fromthe spirit andscopeof this invention as set forth in the appendedclaims.

vWe claim:

l. In an apparatus for the contacting of. uids and solids whichcomprises a contacting vessel, ya foraminate fluid disengaging vessel,and a solids feeder case disposed at successively lower levels in acolumn,l an `inclined solids inlet hopper opening downwardlyrinto theside of said feeder case, an oscillating verticallyacting piston solidsfeeder disposed in said feeder case,l means ,for oscillating andreciprocating said pistonfeeder sci s toY reeivea mass 'of solidslfrbinmsaid'hopper"ridl'fice sagsstgnv wardly through the rising mass ofsolids, the improvement in 4combination therewith of means for agitatingf'the'solids within said contacting section 'which comprises ma.' plowsupport ring, means supporting said support rring in a rotatableposition above the upper end of said contacting section, means forrotating saidsupport ring in ".'this position, a plurality of plowssecured to the lower lsurface "of said support ring and extendingdownwardly intohthe rising mass of solids in said contacting section;"each of said plows comprising a leading' and a'trailing ""h'ollowtubular strut connected at `their upper ends at ftpointsspaced apartfrom each other along an arc around "the center of rotation of saidsupport ring and extending downwardly therefrom at differenthelical'angles into con- "vergence with each other below the upper endof said -eontacting section, an outer cylindrical Vside section se-`"cured tangentially at its leading and trailing edges reispectively tosaid leading and trailing struts substantially -`jat the loci of theoutermost tangent points thereof, Ean 'inner cylindrical side sectionconcentric with said outer sidesection and, secured tangentially at itsleading fand trailing edges respectively to said leading and trailingstruts substantially at the loci of innermost tangentpoints 'fthereof, aplow shoe having' an extended width in a "radial direction relative tothe axis of rotation and se- 'cured to `said helical struts adjacentftheconvergence i'thereof; a plurality'of heat exchange means' supported"ilpon said plow support ring, means connecting said leading andtrailing tubularstruts ofr one of said plows to one of saidY heatexchange means forming therewith a Tclosed fluid iiow circuit, a body ofcoolant filling a 'substantial part of said closed circuit, and meansfor contacting the exterior surface of eachof said heat exchange meanswith a heat exchange medium. 2. An apparatus according to claim 1wherein said means supporting said plow support ring comprises anannular-shaped platform surrounding and connected to said contactingsection adjacent the upper end thereof, a cylindrical ring girder sideframe extending upwardly -`from the outer edge of said platform, a ringgirder extending around the upper periphery of said side frame, aplurality of horizontal and vertical thrustrollers disposed in anduniformly spacedaround the inner surface of said Vriri'g girder, a drivering supported and guided by direct contact with said vertical thrustrollers disposed within said ring girder so as to be rotatable therein,`said drive ring being provided with a radial flange at its upper end,said plow support ring being secured by means of said radial flange tosaid drive ring and rotatable therewith. "3. An apparatus according toclaim 2 in combination with a ratchet ring of T-shaped cross sectionattached to Vaudextending radially outward from the flange at the ftoplof said drive ring and providing on its outer surface airatchetcomprising a plurality of flat vertical surfaces against whichtangential forces are applied, a plurality of hydraulic cylindersdisposed around the periphery of said drive ring, each of said cylindersbeing pivotably secure'd to the inner Surface of said ring girder, aspring loaded ratchet ring engaging head connected at the end 'fof'thepiston rod extending from each of saidrhydraulic cylinders and slidablycoupled to said ratchet ring, whereby hydraulic uid under pressuresupplied toV said cylinders effects drive ring and plow support ringrotation. 4. An apparatus according to claim 2 in combination with anash chute conduit opening downwardly from the y,annular-shapedplatformextending around 'the 'top' of said contacting section,`aplurality of solids scraper elements extending downwardly from saiddrive-ringinto VVthe annular space above said platform and between saidring girder side'frame and the upper part of said contacting section,said scraper elements being spaced apart :.'from one another androtating withV said drive ring tofeim- "'veyspent solids dischargedat'they top of'sard contacting section around said annular space towardentrance to said ash chutecondult.

` through.

the A'upper 5. An apparatus according toclaim 4 in combination with aseal channel disposed around the inner surface tof v'the ring girderside frame, a body of granular solid material filling said channel to asubstantial deptlLfsal element of L-shaped cross section attached toand. extending outwardly and downwardly from the perlpheryof l the drivering into said body of solid material to inhibit iiuid flow between saiddrive ring and said ring girder side frame whereby uid drawn downwardlythrough the contacting section is' forced to enter said .contactingsection via said ash chute conduit in direct countercu'rent heatexchangel relationship to the solids dischargingthere- 6. An apparatusaccording to claim 2 in combination with at least one continuous spacerring disposed "be 'tween the upper flange element of said drivering'and" a peripheral flange disposed around said plow support ring,the presence of which determines the depth to"which said plows extenddownwardly into the contacting section. 7. An apparatus according toclaim 1 whcrein each lof said plurality of heat exchange means disposedup'on s'aid plow support ring comprises a closed shell, sheli'supportmeans connected to the upper deck of said plow support ring, a hotheader conduit and a cold header conduit disposed adjacent the wall ofsaid shell, a plurality o f'ex ternally finned U-shaped heat exchangetubes connected in parallel between said header conduits, means for-circulating a fluid within said enclosure across saidfnne'd tubes, andmeans for controlling the removal andaddition of fluid from and to saidshell, whereby coolant flowing from said plow into and through said heatexchange means and back to said plow is subjected to temperaturecontrol. y

8. An apparatus according to claim 7 wherein 'the coolant circulatedthrough the circuit comprising said plow and heat exchanger meanscomprises a liquidfr'eactive inthe atmosphere, in combination with aninlet and pressure control means therefor opening into the coolantcircuit for an inert gas and adapted to maintain a pressure thereinabove a fixed minimum pressure, and an outlet and pressure control meanstherefor opening from said circuit to maintain pressures thereinvbelow afixed maximum. l

9. An apparatus according to claim 7 in combination with heating meansdisposed within said shell, and heating means disposed adjacent theconduits connecting the heat exchange means to the associated plow, saidheating means being adapted to heat the uid circulated'therein to warmthe coolant during apparatus start-up.A "'f 10. An apparatus accordingto claim 1 in combination with an inner reinforcing cantilever beamelement `contained within said plow structure and comprisinga pluralityof helicoids with their upper ends spaced apart from one another alongsubstantially the same arcas said struts and extending downwardly alongdifferent helical angles into convergence just above the convergence ofsaid leading and trailing struts, a second outer cylindrical sidesection disposed within said plow and adjacent said first-named outerside section thereof and secured to the outer edges of saidhelicoids, asecond inner ycylindrical side section disposed within said plow andadjacent said first named inner side section thereof and secured to theinner edges of said helicoids forming the inner reinforcing cantilever;and curved bearing plates disposed adjacent the convergence of saidhelicoidsand in contact with the leadingand trailing sides of theltrailing and leading tubular struts respectively to load mechanicallythe lower end of rsaid inner reinforcing cantilever with said plow atthis point; said second inner and outer cylindrical side sections, andsaid helicoids being provided along their extended surfaces withapertures to insure the presence of coolanthetwee the double wallsformed by the adjacent pairs of inner and outer side sections andbetween said helicoids, the trailing side of said leading helical strutbeing provided with a coolant outlet into and a coolant entrance fromthe space between the converging helical struts occupied by said innerreinforcing cantilever, said outlet and entrance being locatedrespectively near the bottom and the top of lsaid leading helical strut.

11. An apparatus according to claim 1 in combination with a plowtransition section connecting each of said plows to the lower deck ofsaid plow support ring and which comprises an adapter plate disposedbelow and substantially parallel to the lower deck of said plow supportring, the plate having a shape which is geometrically similar to thehorizontal cross section of said plow at its upper end, the upper endsof said leading and trailing struts and of said inner and outercylindrical side sections being attached to the lower side of saidadapter plate, a leading and a trailing conical section taperingdownward attached at their upper ends to said lower deck and adjacenttheir lower ends to the respective ends of said adapter plate, an innerand an outer conical side section tapering upward and downwardrespectively attached at their upper ends to said lower deck andadjacent their lower ends to the respective sides of said adapter plateand connecting tangentially with said leading and trailing conicalsections and a plurality of strengthening plates disposed within each ofsaid transition sections in vertical planes radially with `respect tothe axis of rotation of said support ring; and wherein said meansconnecting said leading and trailing struts to one of said heat exchangemeans comprises a cold conduit opening upwardly from an opening in saidadapter plate at the upper end of said trailing strut and a hot conduitopening upwardly from another opening in said adapter plate at the upperend of said leading strut, both of which conduits extend through thelower and upper decks of said plow support ring into connection with oneof the superjacent heat exchange means.

l2. An apparatus according to claim l wherein said plow shoe comprises aclosed hollow member elongated from the outer surface of the plowradially inward toward the axis of rotation, the lower surface of Vsaidshoe extending back from the leading radial edge thereof into connectionwith the lower end of said trailing strut and the upper surface ofsaid'shoe extending back and upwardly into the leading strut and thendownward into contact with said lower surface at a point below theconvergence of the adjacent sides of the leading and trailing struts,said plow shoe provided with coolant ow openings to permit coolantentrance into said shoe from said trailing strut and coolant dischargeinto said leading strut, an internal baflle within said shoe to directpart of said ow radially inward and then radially outward inside theleading edge thereof, a wear plate folded over the external surface ofsaid leading edge and spaced apart therefrom by a fluid tight space andsecured at its edges to said shoe, and a volume of high thermalconductivity fusible material substantially lling said space.

13. A heavy-duty apparatus for the agitation of a dense compact mass oflarge size solids which comprises a vessel enclosing said mass ofsolids, a plow support ring, means supporting said support ring in arotatable position above the upper end of said mass of solids, means forrotating said support ring in this position, a plurality ofplows'secured to the lower surface of said support ring and extendingdownwardly into the solids mass; each of said plows comprising a leadingand a trailing hollow tubular strut connected at their upper ends atpoints spaced apart from each other along an arc around the center ofrotation of said support ring and extending downwardly therefrom atdifferent helical angles into convergence with each other below theupper end of said solids l mass, an outer cylindrical side sectionsecured tangentially at its leading and trailing edges respectively tosaidl leading and trailing struts substantially at the loci of theoutermost tangent points thereof, an inner cylindrical side sectionconcentric with said outer side section and secured tangentially at itsleading and trailing edges respectively to said leading and trailingstruts substantially at the loci of innermost tangent points thereof, aplow shoe having an extended width in a radial direction relative to theaxis of rotation and secured to said helical struts adjacent theconvergence thereof.

14. An apparatus according to claim 13 in combination with an innerreinforcing cantileverrbeam element contained within said plow,structure and comprising a plurality of helicoids with their upper endsspaced apart from one another along substantially the same arc as saidstruts and extending downwardly along different helical angles intoconvergence just above the convergence of said leading and trailingstruts, a second outer cylindrical side section disposed within saidplow and adjacent said rst-named outer side section thereof and securedto the outer edges of said helicoids, a second inner cylindrical sidesection disposed within saidplow and adjacent said first-named innerside section thereof and secured to the inner edges of said helicoidsforming the inner reinforcing cantilever; and curved bearing platesdisposed adjacent the convergence of said helicoids and in contact withthe leading and trailing sides of the trailing and leading tubularstruts respectively to load mechanically the lower end of said innerreinforcing cantilever with said plow at this point.

15. An apparatus according to claim 13 in combination with a plowtransition section connecting each of said plows to the lower deck ofsaid plow support ring and which comprises an adapter plate disposedbelow and substantially parallel to the lower deck of said plow sup portring, the plate having a shape which is geometrically similar to thehorizontal cross section of said plow at its upper end, the upper endsof said leading and trailing struts and of said inner and outercylindrical side sections being attached to the lower side of saidadapter plate, a leading and a trailing conical section taperingdownward attached at their upper ends to said lower deck and adjacenttheir lower ends to the respective ends of said adapter plate, an innerand an outer conical side section tapering upward and `downwardrespectively attached at their upper ends to said lower deck andadjacent their lower ends to the respective sides of'said adapter plateand connecting tangentially with said leading and trailing conicalsections, and a plurality-of strengthening plates disposed within eachof said transition sections in vertical planes radially with respect tothe axis of rotation of said support ring.

16. An apparatus according to claim 1 wherein said solids exist at anelevated temperature in combination with self-cooling means for each ofsaid plows which comprises a plurality of heat exchanger enclosuressupported on top of said plow support ring, a hot header conduit and acold header conduit disposed adjacent the wall of said enclosure, aplurality of externally finned U-shaped heat exchange tubes connected inparallel between said header conduits, means for circulating a uidwithin said enclosure across said nned tubes, means for controlling theremoval and addition of Huid from and to said enclosure, a hot conduitopening upwardly from the top of said leading strut into said hotheader, a cold conduit opening downwardly from said hold header into thetop of said trailing strut, a body of coolant lling a substantialportion of the circuit including said struts, conduits, headers, andheat exchange tubes, whereby coolant owing from said plow into andthrough said heat exchange means and back to said plow is subjected totemperature control.

17. An apparatus according to claim 13 wherein said 19 means forsupporting said support ring comprises a cylindrical ring girder sideframe extending upwardly around the mass of said solids,`a ring girderextending around the upper periphery of said side frame, a plurality ofhorizontal and vertical thrust rollers disposed in and uniformly spacedaround the inner surface of said ring girder, a drive ring supportedandy guided by direct contact with said vertical thrust rollers disposedwithin said ring girder so as to be rotatable therein, said drive ringbeing provided' with a radial flange at its upper end, said plow supportring being secured by means of said radial flange to said drive ring androtatable therewith, and wherein said means for rotating said supportring comprises a ratchetring of T-shaped cross section attached to andextending radially outward from the flange at the top of said drive ringand providing on its outer surface a ratchet comprising a plurality offlat vertical surfaces against which tangential forces are applied, aplurality of hydraulic cylinders disposed around the periphery of saiddrive ring, each of said cylinders being pivotably secured to the innersurface/of said ring girder, a springloaded ratchet ring engaging headconnected at the end of the piston rod extending from each of said'hydraulic cylinders and slidably coupled to said ratchet ring, wherebyhydraulic fluid `under pressure supplied to said cylinders effects drivering and plow support ring rotation.

18. An apparatus according to claim 17 in combination with at least onecontinuous 'spacer ringdisposed between the upper flange element of saiddrive ring and a peripheral flange disposed around said plow'supportring, the presence -of which determines the'depth to which said plowsextend downwardly into said dense mass of solids.

19. An apparatus according to claim 13 wherein said plow shoe comprisesa closed hollow member elongated from theou`ter surface of the plowradially inward toward the axis of rotation, the lower surface of saidshoe extending back from the leading radial edge thereof into connectionwith the lower end ofv said trailing strut and the upper surface of saidshoe extending back and upwardly into theleading strut and then downwardinto contact with said lower surface at a point below the convergence ofthe adjacentsides of the leading and trailing struts, said plow shoeprovided with coolant flow openings to permit coolant entrance into saidshoe from said trailing strut and coolant discharge into said leadingstrut, an internal baille within said shoe to direct part of said flowradially inward and then radially outward inside the leading edgethereof, a wear plate folded over the' external surface of said leadingedge and spaced apart therefrom by a fluid tight space and secured atits 420 edges to said shoe, and a volumeof high thermal conductivityfusible material substantially filling said space.

20.` An apparatus according to claim 13 in combination with a pluralityof parallel substantially horizontal void sealing plates spaced apartfrom each other and secured tothe rearward surface of said trailingstrut, said plates being provided to inhibit flow of fluid through thesolids mass immediately behind said trailing strut.

21. An apparatus according to claim 13 in combination with means forreceiving said solids at alower level within said vessel and forcingsaid solids upwardly into and through said vessel, thereby dischargingsaid solids at the topl thereof of said vessel;

22. An apparatus according to claim 21 wherein said solids exist atanelevated temperature in combination' with self-cooling means for each ofsaid plows which comprises a plurality of heat exchanger enclosures supported on top of saidplow support ring, a hot header conduit and a coldheader conduit disposed adjacent the wall of said enclosure, a pluralityof `externally finned U-shaped heat exchange tubes'connected in parallelbesubstantial portion of the circuitA including said struts,

conduits, headers, Aand heat exchange tubes, whereby coolant flowingfrom said plow into and through said heat exchange means and back tosaid plow is subjected to temperature control.

23. A heavy-duty apparatus according to claim 13 inl whichthe vesselcommunicates at its lower end with the upper end of a foraminatefluiddisengaging vessel, the

lower end of the disengaging vessel communicates with means for forcingsaid solids upwardly through said disengaging vessel and said vesselenclosing said mass of solids,v a closed-separatorvessel surrounds saiddisengaging vessel, and means are provided for removing fluids therefromto maintain flow of fluid downwardly through the rising mass of solids.

References Cited in the file of this patent UNITED STATES PATENTS176,851 Force p May 2, 1876 1,341,287 Somerville May 25, 1920 2,640,019Berg May 26, 1953 2,698,283 Dalin Dec. 28. 1954

1. IN AN APPARATUS FOR THE CONTACTING OF FLUIDS AND SOLIDS WHICH COMPRISES A CONTACTING VESSEL, A FORAMINATE FLUID DISENGAGING VESSEL, AND A SOLIDS FEEDER CASE DISPOSED AT SUCCESSIVELY LOWER LEVELS IN A COLUMN, AN INCLINED SOLIDS INLET HOPPER OPENING DOWNWARDLY INTO THE SIDE OF SAID FEEDER CASE, AN OSCILLATING VERTICALLY-ACTING PISTON SOLIDS FEEDER DISPOSED IN SAID FEEDER CASE, MEANS FOR OSCILLATING AND RECIPROCATING SAID PISTON FEEDER SO AS TO RECEIVE A MASS OF SOLIDS FROM SAID HOPPER AND FORCE IT UPWARDLY INTO AND SUCCESSIVELY THROUGH SAID DISENGAGING AND CONTACTING SECTIONS, A CLOSED SEPARATOR VESSEL SURROUNDING SAID DISENGAGING VESSEL, AND MEANS FOR REMOVING FLUIDS THEREFROM TO MAINTAIN FLOW OF FLUID DOWNWARDLY THROUGH THE RISING MASS OF SOLIDS, THE IMPROVEMENT IN COMBINATION THEREWITH OF MEANS FOR AGITATING THE SOLIDS WITHIN SAID CONTACTING SECTION WHICH COMPRISES A PLOW SUPPORT RING, MEANS SUPPORTING DAID SUPPORT RING IN A ROTATABLE POSITION ABOVE THE UPPER END OF SAID CONTACTING SECTION , MEANS FOR ROTATING SAID SUPPORT RING IN THIS PSOITION, A PLURALITY OF PLOWS SECURED TO THE LOWER SURFACES OF SAID SUPPORT RING AND EXTENDING DOWNWARDLY INTO THE RISING MASS OF SOLIDS IN SAID CONTACTING SECTION; EACH OF SAID PLOWS COMPRISING A LEADING AND A TRAILING HOLLOW TUBULAR STRUT CONNECTED AT THEIR UPPER ENDS AT POINTS SPACED APART FROM EACH OTHER ALONG AN ARC AROUND THE CENTER OF ROTATION OF SAID SUPPORT RING AND EXTENDING DOWNWARDLY THEREFROM AT DIFFERENT HELICAL ANGELS INTO CONVERGENCE WITH EACH OTHER BELOW THE UPPER END OF SAID CONTACTING SECTION, AN OUTER CYLINDRICAL SIDE SECTION SECURED TANGENTIALLY AT ITS LEADING AND TRAILING EDGES RESPECTIVELY TO SAID LEADING AND TRAILING STRUITS SUBSTANTIALLY 